Radio ground control equipment for aircraft



N0v 10, 1953 B, F. COLLINS ETAL RADIO GROUND CONTROL EQUIPMENT FOR AIRCRAFT Filed June 6, 1950 LAMP #f1/73am; MARI) M m m\ F. w d s 24.. 9 2 HHM 4 9 LLll d A@ 2 G F I Attorney.;

Patented Nov. 10, 1953 FFICEQ RADIO GROUND CONTROL EQUIPMENT FOR AIRCRAFT Bernard F. Collins, Eastwood, Victor J. Cox,

. Malmesbury, and Anthony W. Martin, Thundersley, England, assignors to E. K. Cole Limited, Southend-on-Sea, England Application June 6, 195o, serial No. 166,406

`Claims priority, application Great Britain June 15, 1949 Claims.

For complete ground control of an aircraft approach it is necessary to have (a) the range from the runway (b) bearing (c) height. In a comprehensive radar system this information is derived from two aerial systems, one scanning in azimuth and the other in elevation, which present to the operator on his cathode ray tube indicator two plan position indications for bearing and height respectively.

Such a system apears to be necessary when it is desired to control several aircraft simultaneously, but its complexity and cost as well as the number of stanc usually7 required for its operation, put it out of reach of the smaller airports with limited tralc.

The object of the present invention is to provide a simpler and cheaper form of approach and landing aid. Accordingly the invention is not concerned with apparatus in which a radar aerial is continuously rotated in one direction about a vertical axis. In such an apparatus the radar beam searches continuously in all directions picking up Whatever may be in its path. On the other hand the present invention uses a radar aerial of a type which is aimed or sighted by an operator. The term non-continuously rotated aerial is used herein to mean an aerial of this latter type.

In the continuously rotated aerial arrangement, the radar beam is narrow only in one plane whereas in the present invention the radar beam is narrow in all planes, including both the azimuth plane and the perpendicular` plane. Such a narrow radar-beam may be described as a pencil beam, and this terminology is accordingly used in the appended claims to designate such a narrow beam which may be aimed toward a distant object.

When an aircraft is more than, say, twelve vmiles from a ground control station the pilot usually requires the operator thereat to give him a bearing only. This is done by ordinary radio communication from information given by the direction finder (D. F.) at the operators position. It is only when the pilot, nearing the aireld, desires to land that additional information and guidance are required.

For this reason the present invention is most useful, for at a relatively small cost the apparatus enables all the above information to be given, the apparatus comprising a relatively long-range D. F. enabling the bearing to be given and automatically conditioning a short-range radar equipment to be used when the pilot is nearingI the airneld.

A feature of the present invention is a ground control apparatus for aircraft comprising a direction lnder having a directional aerial adapted to be moved manually about a vertical axis and mechanically coupled to a pencil beam radar aerial of the non-continuously rotated type so that on the bearing of an aircraft havingbeen located by the direction finder the radar aerial will be directed to the azimuth bearing of the aircraft, means for separately moving the radar aerial about a horizontal axis and the radar aerial being coupled to a cathode ray tube, on

the viewing screen of which a trace is produced.

which is adapted to indicate the range of the aircraft from the control apparatus.

The employment of a direction finder (D. F.) of the said type is not an additional expense because such a direction finder is necessary in any case to obtain direction at distances exceeding the range of a radar system of reasonable power. Y

For convenience the term "radar aerial is used to include the usual aerial assembly comprising aerial, reflector and dish.

'I'he above and other features of the invention will be made clear in the appended claims and in the following description of one embodiment. In the accompanying drawings, Figure 1 is a front elevation showing diagrammatically a complete apparatus according to the invention and Figure 2 is a sectional side elevation of the parts shown in Figure 1.

The apparatus comprises a D. F. aerial array l fixed to a hollow vertical shaft 2 which is supported inthe roof of a truck 3 in a bearing 4 which is adapted to rotate in said roof. To the shaft 2 is also fixed a radar aerial 5 which is pivoted on a bracket S which is anchored to the shaft 2. The radar aerial 5 may be moved through a vertical angle by actuating a control rod 'I whose lower extremity is connected to one end of a quadrant lever 8, the quadrant end meshing with a spur wheel 9 mounted'on a steering rod l!) which is rotatable on its axis in bearings mounted on a bracket l l anchored to the shaft 2. The steering rod I0 carries a scale l2 which moves over a stationary cursor to give an indication of thecant of the radar aerial vaccording to the different positions of rotation of the steering rod I 0. A wave guide I 3 has connections to a radar. transmitter/receiver lll which comprises a cathode ray tube l5 upon which a trace V(somewhat as indicated) is adapted to be produced by signals received in the radar aerial., Theshaft 2 .is adapted to be .uned about its axis by moving the steering od l in a horizontal plane, the angle of moveient being indicated by a cursor I6 and a iixed :ale I1. Leads from the D. F. aerial pass .irough the shaft 2 to the D. F. receiver i8 of rdinary type. I9 is a sense aerial adapted to be onnected to one of the aerials i for obtaining he sense in the D. F. for direction finding in the .ormal manner. The cursor I6 is adapted .to .be et against a reading on the scale l1 according o the angle subtended by the landing strip with espect to the position of the apparatus, andV he arrangement is such that, should the shaft be rotated through more than a predetermined ,ngle, say 3/4 on either side of the cursor set-'- ing, lamps 20 or 2l at the sides of the cathode ay tube would be illuminated to indicate to the lperator watching the cathode ray screen that he permissible deflection had been exceeded. iimilar lamps 22 and 23 at the top and bottom of he cathode ray tube support respectively are in circuit controlled by a switch operated by the cale I2 so that if the steering rod l0 be turned about its axis more than say 1/2" from the preletermined angle of flight, lamps 22 or 23 would :e lit. It is thus obvious from the small preletermined angles of permissible deflection that he radar beam may be conveniently describeda-s l. pencil beam, being narrow in all directions in t plane at right-angles to the axis of the beam. ['he bracket 6 is conveniently fixed to the shaft by means of a set screw 24, whilst strength is given tothe iixture by means of the legs 25 iixed ;o a lower bracket 2B, securedl to the shaft 2 by i set screw 21.

The radar equipment I4 may be of the type yell known by those skilled in the art, the only variation being that the frame scanning equipnent is omitted. They cathode ray tube screen .ndication will be in the form somewhat as shown in Figure 1 at l5. The device is provided with yhat is usually termed a range marker generator which, b'y closing a switch (usually a pressbutton), causes the trace on the screen to be olanked out over small distances at regular i-ntervals of space. These may alternatively be at say, .1/2-rnile intervals or 21k-mile intervals according to the switch, or may beV switched so as to be Vnon-effective. Thus, looking at l5 in E'igure l, the initial peak on the trace would be the transmitted pulseJ whilst the second peak would be the result of a received Wave causedr by the reection of the transmittedV pulse from'a distant object. If. the marker generator were set for 2-1/2-mile intervals and the first -space (counting from the first peak) appeared .against Y the second peak it would indicate that theV range of the distance object was 21/2 miles from the ground station.

In operation the direction nder ,is used in the normal manner to locate the direction of anv zontal axis and'bring the aircraft indication onV to the screen of his cathode ray tube. By intercommunication the .operator Acould inform the 4 cathode ray tube. When the aircraft has been brought into the correct line of approach, the operator could without taking his attention from the screen keep the pilot advised of his range and could keep him in the correct line of approach and height. If the pilot left this line by more than a predetermined amount, the operator would be warned by the lighting of the lamps tinually manipulating 'the steering rod. to keep the aircraft indication on the screen Vof `his.

2.0, .2l on one side or the other of the screen, Whilst if the height varied more than a predetermined amount from that Which was indicated by the correct Vangle of approach, the lamps 22, 3V at the top or bottom of the screen would be illuminated.

' The ground equipment Would be positioned in line with the run-Way to be used, its'position being near that end which the pilot would first reach in making a landing. The cursor on the azimuth scale would be set at the bearing representing that subtended by his equipment with regard to the run-way and hence if the D. F. aerials were swung more than from this position in either direction either one set or the other of the side lamps would light. Similarly, the cursor on the elevation scale would be set at the required vertical angle of approach say 5, and any canting of the radar aerial more than at say 1/2" from this angle would be indicated by lamps at the top or bottom of his screen.

While we have described only one embodiment of the invention it is to be understoodthat We are not limited to the particular details thereof, since various modifications and substitution of equivalents may be made by those skilled in the art, without departing from the invention as defined in the following claims,

We claim:

l. In -a ground control appartus forY aircraft, a direction finder comprising an aerial of the type which is manually rotatable to the direction of a distantV transmitter, a direction-indicating instrument coupled to said aerial, a pencil beam radar aerial of the non-continuously rotated type said radarxaerial being coupled to a radar transmitter/receiver 'having a cathode ray viewing screen, a vertical shaft fixed to vsaid directionnding aerial and to a bracket having a pivot supporting the radar aerial for vertical movement about lsaid pivot, manually operable means for moving thevertical shaft about its axis and means for moving the radar aerialY vertically about said pivot Vwhereby the radar beam may be aimed at a distant object, a nrst means for indicating the angle in azimuth of both said radar aerial and. said direction-iinding aerial, anda secondV indicating means for indicating the vertical angle of said radar aerial'.

2. In a ground control apparatus for aircraft, a direction finder comprising an aerial of the type which is manually rotatable to the direction of a distant transmitter, a direction-indicating instrument coupled to. said aerial, a pencil beam radar vaerial of the non-continuously rotated.

rodto said'vertical shaft vfor rotating said vertical shaft about. its Vaxis and meansl operatively connecting .said steering rodto said radar aerial .for

" 'moving said radar aerial vertically aboutV said pivot whereby the radar beam may be aimed at a distant object, a first means for indicating the angle in azimuth of both said radar aerial and direction-nding aerial, a second indicating means for indicating the vertical angle of said radar aerial, means for pre-setting a desired angle on said rst indicating means, and means for pre-setting a desired angle on said second indicating means.

3. In a ground control apparatus for aircraft, a direction iinder comprising an aerial of the type which is manually rotatable to the direction of a distant transmitter, a direction-indicating instrument coupled to said aerial, a pencil beam radar aerial of the non-continuously rotated type, said radar aerial being coupled to a radar transmitter/receiver having a cathode ray viewing screen, a vertical shaft iixed to said directioniinding aerial and to a bracket having a pivot supporting the radar aerial for vertical movement about said pivot, manually operable means for moving the vertical shaft about its axis and means for moving the radar aerial vertically about said pivot whereby the radar beam may be aimed at a distant object, a rst means for indicating the angle in azimuth of both said radar aerial and said direction-iinding aerial, a second indicating means for indicating the vertical angle of said radar aerial, a warning device, means to operate said warning device when said vertical shaft is moved more than a predetermined amount beyond the limits of said azimuth angle, and means to operate said warning device when said radar aerial is moved more than a predetermined amount beyond the limits of said vertical angle.

4. In a ground control apparatus for aircraft, a direction iinder comprising an aerial of the type which is manually rotatable to the direction of a distant transmitter, a direction-indicating instrument coupled to said aerial, a pencil beam radar aerial of the non-continuously rotated type, said radar aerial being coupled to a radar transmitter/receiver having a cathode ray viewing' screen, a vertical shaft fixed to said directionnding aerial and to a bracket having a pivot supporting the radar aerial for vertical movement about said pivot, a manually operable steering rod, means operatively connecting said steering rod to said vertical shaft for rotating said vertical shaft about its axis and means operatively connecting said steering rod to said radar aerial for moving said radar aerial vertically about said pivot whereby the radar beam may be aimed at a distant object, a rst means for indicating the angle in azimuth of both said radar aerial and direction-finding aerial, a second indicating means for indicating the vertical angleof said radar aerial, means for pre-setting a desired angle on said rst indicating-means, means for pre-setting a desired angle on said second indicating means, a Warning device, means to operate said warning device when said vertical shaft is moved more than a predetermined amount beyond the limits of said azimuth angle, and means to operate said Warning device when said radar aerial is moved more than a predetermined amount beyond the limits of said vertical angle.

5. In a ground control apparatus for aircraft, a direction finder comprising an aerial of the type which is manually rotatable to the direction of a distant transmitter, a direction-indicating instrument coupled to said aerial, a pencil beam radar aerial of the non-continuously rotated type, said radar aerial being coupled to a radar transmitter/receiver having a cathode ray viewing screen, a vertical shaft xed to said directionnding aerial and to a bracket having a pivot supporting the radar aerial for vertical movement about said pivot, a manually operable steering rod, means operatively connecting said steering rod to said vertical shaft for rotating said vertical shaft about its axis and means operatively connecting said steering rod to said radar aerial for moving said radar aerial vertically about said pivot whereby the radar beam may be aimed at a distant object, a rst means for indicating the angle in azimuth of both said radar aerial and directiOn-nding aerial, a second indicating means for indicating the vertical angle of said radar aerial, means for pre-setting a desired angle on said first indicating means, means for presetting a desired angle on said second indicating means, lamps located on each side of said viewing screen, means responsive to swinging movement of said steering rod to operate said lamps when said steering rod is swung more than a predetermined amount beyond the limits of said azimuth angle, lamps located above and below said viewing screen, and means responsive to turning movement of said steering rod about its horizontal axis to operate said last-named lamps when the steering rod is turned more than a predetermined amount beyond the limits of said vertical angle.

BERNARD F. COLLINS. V'. J. COX. A. W. MARTIN.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date Y 2,368,298 Harris Jan. 30, 1945 2,405,231 Newhouse Aug. 6, 1946 2,421,028 King May 27, 1947 2,428,793 Fay Oct. 14, 1947 2,471,264 Doherty May 24, 1949 2,526,314 Alexanderson et al. Oct. 17, 1950 2,585,855 Sherwin et al Feb. l2, 1952 2,597,895 Novy May 27, 1952 

